As for a damper buffering an impact applied from outside, there is known a rotary damper. The rotary damper provides a damping force that attenuates a torque to a rotor shaft by a resistance when a rotor rotates inside an attenuating medium having fluidity such as oil and the like.
As for the rotary damper, there is proposed a damper using a material having viscosity as the attenuating medium (for example, see Patent Document 1). In this damper, the rotor rotates while shearing the viscus material so as to generate the damping force, thereby, a large damping force can be obtained without enlarging the damper.